P1AC6
DTC P1AC6 or P1AC7
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P1AC6
- Drive Motor 1 Control Module Crankshaft Position Sensor Circuit
DTC P1AC7
- Drive Motor 1 Control Module Crankshaft Position Sensor Performance
Diagnostic Fault Information
Circuit/System Description
The crankshaft position (CKP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. The CKP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The CKP sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the CKP sensor output depends on the velocity of the crankshaft. The CKP sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the CKP sensor. The ECM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The ECM also uses CKP sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire, and to control the CMP actuator if equipped.
Motor Control Module (MCM) 1 is also connected to the CKP sensor signal and low reference circuits. The MCM uses the CKP sensor output information to determine engine crankshaft position to aid in smooth engine Auto-starts.
Conditions for Running the DTC
DTC P1AC6 and P1AC7
* Drive motor generator 1 is rotating.
* The DTC runs continuously when the above conditions are met.
Conditions for Setting the DTC
DTC P1AC6
The HCM detects no engine speed signal for 2 seconds.
DTC P1AC7
MCM 1 detects no engine speed signal for 3.1 seconds.
Action Taken When the DTC Sets
DTCs P1AC6 and P1AC7 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P1AC6 and P1AC7 are Type B DTCs.
Diagnostic Aids
With an ECM DTC P0335 set, the engine will only crank for about 2 seconds.
Circuit/System Verification
Inspect for ECM P0335 or ECM P0336. With the engine running, observe the hybrid control module Engine Speed parameter with a scan tool. The parameter should display the current engine speed, matching the tachometer and/or the ECM Engine Speed parameter.
If ECM DTCs P0335 or P0336 are set, diagnose them prior to diagnosing the hybrid powertrain control module (HPCM) DTC.
If the Engine Speed parameter displays a value other than the current engine speed, continue with Circuit/System Testing.
Circuit/System Testing
Important: Diagnose ECM DTCs P0335 and P0336 prior to performing this procedure.
1. Ignition OFF, disconnect PIM connector X1 and the CKP sensor connector.
2. Test for less than 5 ohms of resistance on the CKP low reference circuit, from connector X1 terminal 35 and ground.
^ If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the engine control module.
3. Ignition ON, test for 4.8-5.2 volts on the CKP signal circuit, from the connector X1 terminal 26 and ground.
^ If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the drive motor generator power inverter control module (PIM).
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests